The invention relates to the management of connection-oriented telecommunications systems, and more particularly, to a technique for reusing core telecommunications system resources during periods of inactivity of a connection that does not bring with it a concomitant need for re-origination of the call when the connection is no longer dormant.
The demand for telecommunications services has been growing at an ever-increasing rate. One of the factors behind this increasing demand for telecommunications services has been the growing popularity of online data communications (xe2x80x9cdatacomxe2x80x9d) services such as those based on the Internet. In order to meet this demand, telecommunications network operators and suppliers have had to continuously upgrade the traffic carrying capacity of both their circuits as well as of the switch nodes interconnecting those circuits.
It has been observed that the demand for ordinary voice telephone service is becoming a decreasingly smaller part of the overall traffic demand in comparison to other telecommunications services such as data communications between computers, graphical image transmissions, video-conferencing and similar broadband services.
Current and future telecommunications subscribers, both residential and business, are likely to be connected, via common accesses, to a web of broadband networks operating at data rates of 150 megabits per second or above and which can support a wide range of different types of broadband services. Broadband networks may be generally defined as those which support user services requiring bit transfer rates substantially in excess of one megabit per second.
In general, broadband networks are likely to be built using Asynchronous Transfer Mode (ATM) technology as the underlying type of transport and switching technology. Broadband Integrated Services Digital Networks (B-JSDN), employing ATM technology can offer users the flexibility and capacity necessary to support diverse telecommunications services ranging from basic voice telephone service to high speed data transfer, video telephony, and high-quality television signal distribution. As would be obvious to those of ordinary skill in the art, ATM technology relies upon the compartmentalization of data into packets or cells which are transmitted and switched as individual units through the various nodes of a broadband network.
Current large telephone central offices may serve up to 100,000 customers. Based upon such a large number of terminals, a future B-ISDN central office may be required to operate at a switching capacity of around one terabit per second (1012 bits per second) or greater. Assuming that each customer is served with a B-ISDN line operating at the design throughput level of 155.52 megabits per second (the STM-1 rate), an ATM exchange switch needs to be able to handle a peak throughput in excess of 15 terabits per second. However, in practice, the average throughput (i.e. the bandwidth utilization rate) is likely to be substantially lower than 15 terabits per second due to the inherent burstiness of datacom traffic on many levels.
Telecommunications equipment capable of handling high switching rates are expensive. consequently, it is desirable that such equipment be utilized as much as possible. Since the average additional revenue that may be realized by improving the utilization rate of the telecommunications equipment is higher at the core than at the periphery, there is a strong incentive for seeking increased efficiency in using core telecommunications resources.
For the purposes of the present patent application, the core telecommunications resources principally refer to the switching and transport resources that are located between and within a local exchange and a remote subscriber station (or more generally between network adaptors and a terminal) Under the traditional design paradigm for telecommunications systems, such core resources can be ordinarily be easily reallocated to other users or applications provided that transmission activity on a circuit-switched telephony connection can be monitored to detect periods of quiescence.
In the current era of explosive growth in data traffic due to the Internet, lots of subscribers use their personal computers to access the Internet via dial-up connections through their Internet Service Provider (ISP). In most regions of the United States of America, ISPs can be dialed as local calls. consequently, most users do not incur toll charges from their local telephone company in accessing their ISP.
Furthermore, most ISPs offer fixed-price access to the Internet. Thus, most users do not pay hourly charges for accessing the Internet. These factors have led to a vast increase in the data traffic on the telephone network. Thus, the unlimited simple and fixed price access to the Internet and other similar online services has led to a problem, colloquially referred to as the problem of xe2x80x9cmodem camping.xe2x80x9d
In brief, the xe2x80x9cmodem campingxe2x80x9d problem arises when a subscriber accessing an on-line services through a modem uses the available bandwidth of the transmission channel only sporadically. This results in an entire end-to-end circuit-switched telephony connection being rendered unavailable to other (more active) users.
It would be especially useful if an inactive data communication session could release the connection resources (both switching and transport) for use by others. As explained earlier, it would be best to start on this task by detecting and releasing core telecommunications resources that have been allotted to currently inactive connections.
Unlike voice traffic, data communications (xe2x80x9cdatacomxe2x80x9d) traffic is inherently xe2x80x9cburstyxe2x80x9d. This means that the average traffic on a datacom link may be significantly different from the instantaneous traffic on the link. Furthermore, interactive computer applications typically generate discontinuous traffic patterns having long periods of inactivity.
For example, a user browsing the Internet may download an image from a remote web site. The telephone connection between the subscriber and the subscriber""s Internet Service Provider (ISP) will on average be heavily loaded every time a graphical image file is accessed or downloaded by the subscriber. However, such periods of heavy utilization of the telephone connection are likely to be interspersed with extended periods of little or no activity.
The amount of time that a connection remains dormant has been found to depend upon many factors such as user behavior, the computer algorithms used and the sizes of the buffers in the various processors along the route. The use of circuit-switched telephony connections for handling datacom traffic is likely to result in the wastage of connection resources (including both switching and transport resources). This is because circuit-switched telephony connections traditionally provide an invariant connection resource (in terms of both switching and transport resources) between the two end points of the circuit. Consequently, all resources allocated to the telephony circuit remain blocked even during long periods of inactivity.
Recent attempts to reduce the wastage of connection resources within circuit-switched data communication links have focused on using xe2x80x9con-demandxe2x80x9d dial-up connections that repeatedly dial-up and reestablish an end-to-end connection upon the detection of renewed activity. Simultaneously, the end-to-end session is kept active (xe2x80x9calivexe2x80x9d) even during periods of inactivity.
This technique for increasing the utilization efficiency of intermediate link resources requires a dialed-up connections be reestablished several times during a single session. consequently, the current technique involves repetitive signaling, processing and resource-handling and imposes additional demands on the signaling and management subsystems of the telecommunications network.
Establishing a dialed-up connection consumes control system resources (e.g., signaling and processing resources) each time a new connection is established or reestablished. The set-up processing of a dialed-up connection is rarely instantaneous and hence results in additional transmission delays and a concomitantly wastage of processing resources. This is because telephone numbers, user authenticity, access rights, user service profile (and sometimes) routing and charging issues need to be analyzed anew every time a new call is made.
Part of the additional costs of using the repeated dial-up technique also follows from the fact that call-related information structures and charging records need to be built up anew for each re-dialed connection. The use of the repeated dial-up technique to improve the utilization of connection resources invariably causes the signaling and processing costs of each dial-up to be incurred multiple times during a single session. This results in a substantial increase in the signaling and processing costs on a per-session basis.
It would therefore be desirable to have a technique for utilizing scarce call and connection resources (including switch, transport, signaling and processing resources) in an efficient manner that permits a datacom application to use a circuit-switched telephony connection on demand in a dynamic application controlled manner without requiring a call to be reestablished periodically by re-dialing.
It would be desirable if connection set-up resources such as key code receivers, tone generators and processors were invoked and used only once for each session of a datacom application. Additionally, it is desirable if the slow connection-establishment times associated with the current repeated dial-up technique is speeded up by eliminating or replacing the transmission and analysis of multiple B-numbers with a faster and simpler wake-up signal. The use of a wake-up alert can lead to higher resource utilization and reduced processing load on core telecommunications resources.
It would be desirable if some or all of the connection resources that are not being used during a datacom session were released and made available for use by other active datacom sessions or voice-connections. Such an enhancement to the art could enable the sharing (and increase the utilization) of connection resources. This can prove especially useful to increase the speed and reduce the cost of providing new data access services.
It has also been found desirable to have the access routers serving a datacom access gateway to be centralized and compatible with multiplexing techniques such as time-sharing. It has additionally been found desirable to provide secure and low-cost connection to Internet Service Providers (ISPs), to facilitate telecommuting and to provide enterprise-wide access to networks and services. It would also be desirable if a solution to the problem of modem-camping were made compatible with emerging applications such as electronic commerce.
There has been a long-felt need for low-cost and secure telephony-based connection that can also permit data communication between multiple peer personal computers (PCS), and facilitate the agglomeration of small Local Area Networks (LANs) into a Wide Area Network and the creation of Virtual LANs (VLANs).
It is therefore a primary object of this invention to permit a datacom application to use a circuit-switched telephony connection on demand without requiring repeated dial-ups. It is an additional object of the present invention to permit a datacom application to dynamically reactivate a circuit-switched telephony connection.
Yet another object of the present invention is to permit a datacom application program to control the invocation and release of a circuit-switched telephony connection. It is an additional object of the subject invention to permit the release of core telecommunications resources during periods of inactivity in a data communication session.
It is an additional object of the present invention to permit adaptive disconnection and/or reactivation of physical resources based upon the overall load on the system at any given time. It has been found desirable to avoid the release of telecommunications resources whenever the overall load on (or resource utilization rate of) a telecommunications system is low. Another object of the present invention is to permit the allocation and reestablishment of connection resources to be controlled by priority levels assigned to subscribers based upon the intended use and/or contractual subscription arrangements.
It is also an object of the present invention to permit data structures associated with a specific circuit-switched telephony connection to be maintained even while some or all of the core connection resources have been (temporarily) released and reutilized.
In one aspect, the dynamic connection system and method of the present invention increases the efficiency of utilization of core telecommunications resources by a data communications (xe2x80x9cdatacomxe2x80x9d) application program operating on a connection-oriented telecommunications network. The dynamic connection technique reallocates system resources on the most valuable segment of an end-to-end connection between an origination point and a termination point. The dynamic connection technique is amenable to dynamic control by the datacom application program.
The technique is enabled by first partitioning an end-to-end connection into two or more segments. At least one, a first, of the segments should contain core telecommunications resources associated with the end-to-end connection. Transmissions over the end-to-end connection are continuously monitored till a period of quiescence is detected on the connection for a preselected period of time.
When such a period of inactivity is detected, the first segment of the connection is deactivated (i.e. put into a paused state). The core telecommunications resources associated with the deactivated first segment are released for reuse by other, active applications, causing the end-to-end connection to become dormant.
Transmission activity or attempts in segments other than then first segment of the end-to-end connection is then monitored till renewed transmission activity is detected in a segment other than the now deactivated first segment. Upon F the detection of such renewed activity, the dormant end-to-end connection is reactivated subject to resource and other system constraints.
The dynamic connection technique of the present invention can be used with both analog (inband) signaling systems (e.g., Plain Old Telephone Service or POTS) as well as with digital signaling systems (e.g., Integrated Services Digital Network or ISDN). The deactivation and reactivation of core telecommunications resources can be performed using various priority schemes.